A reactor is one of components of a circuit performing a voltage step-up operation or step-down operation. For example, Patent Literatures 1 to 3 disclose reactors for use as circuit components of converters mounted on vehicles such as hybrid cars. The reactor typically includes a coil having a pair of coil elements, and an annular magnetic core having the coil elements arranged side by side such that the axial directions of the coil elements are parallel to each other (see, in particular, Patent Literatures 1 and 2).
Patent Literature 1 discloses a reactor including an outer case accommodating an assembly of a coil and a magnetic core, resin filling the inside of the outer case to seal the assembly, and an insulating member interposed between the coil and the magnetic core for insulation therebetween. The insulating member includes a tubular bobbin arranged on the outer circumference of the magnetic core and a pair of frame-like members arranged on opposite end surfaces of the coil. The coil sandwiched by the frame-like members is accommodated in a bracket-shaped inner case, which is then accommodated in the outer case. Patent Literature 3 discloses a reactor including a resin portion that covers an outer circumference of an assembly of a coil and a magnetic core. In use, these conventional reactors are installed on a fixed object such as a cooling base such that the coil heated with application of current can be cooled.